The edge structure, such as the edge beam, of a concrete bridge is often built separately after constructing the deck of the bridge. There thus is a need for a scaffold usable for building the edge structure. The edge structure is also susceptible to damage over time e.g. due to disintegration of the concrete, providing a need to repair the edge structure.
The closest prior art is represented by a scaffold arrangement comprising a casting mould and an access bridge supported onto the same scaffold that is suspended from the edge of the bridge. The arrangement comprises a number of bents arranged at a distance from each other for the length of the area of the bridge that needs repairing and supported onto the edge of the bridge by support members. The access bridge is supported onto the bents in order to form a passage for the duration of the repair period. Mould walls are supported onto the bents in order to form a concrete casting mould for casting the new edge structure for the bridge.
The problem with all known scaffold arrangements is that in order to provide a sufficiently tight mounting, the mounting of the scaffold has required the formation of holes extending through the entire deck of the bridge. In other words, the bents have been suspended by the bars extending through the above-mentioned holes. To mount such scaffolds, the workers have been forced to work for extended periods from underneath the bridge, by means of e.g. a passenger lift or, if possible, a so-called bridge crane positioned onto the deck. Long-term work on/under the bridge with lifting machines disturbs road traffic and often also railway traffic. Moreover, the mounting is difficult in bridges which cross waterways. With the known methods and arrangements, for example the construction of a scaffold arrangement required for repairing the edge beam of a bridge has taken a long time. Long mounting and repair periods hinder the traffic and increase the expenses. Furthermore, the present scaffolds are usually made of timber, so that the scaffolds are disassembled after the work is completed, and only a portion of the stouter timber may be reused, the rest ending up on a landfill site as unserviceable.